<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>绝对定位</title>
    <style>
        .c1{
            /* 脱离了文档流了.. */
            position: absolute;
            width: 80px;
            height: 80px;
            background-color: #330000;
            left: 20px;
            top:20px;
        }

        .c2{
            width: 200px;
            height: 200px;
            background-color: red;
        }
    </style>
</head>
<body>
    <div class="c1">

    </div>

    <div class="c2">
        dfdfd
    </div>
</body>
</html>